// Copyright (c) 1999 Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $Source: /CVSROOT/CGAL/Packages/H2/include/CGAL/Homogeneous/VectorH2.h,v $
// $Revision: 1.21 $ $Date: 2004/05/19 13:29:32 $
// $Name: $
//
// Author(s) : Stefan Schirra
#ifndef CGAL_HOMOGENEOUS_VECTOR_2_h
#define CGAL_HOMOGENEOUS_VECTOR_2_h
#include <CGAL/Origin.h>
#include <CGAL/Threetuple.h>
CGAL_BEGIN_NAMESPACE
template < class R_ >
class VectorH2
{
typedef typename R_::FT FT;
typedef typename R_::RT RT;
typedef typename R_::Point_2 Point_2;
typedef typename R_::Segment_2 Segment_2;
typedef typename R_::Ray_2 Ray_2;
typedef typename R_::Line_2 Line_2;
typedef typename R_::Direction_2 Direction_2;
typedef typename R_::Vector_2 Vector_2;
typedef typename R_::Aff_transformation_2 Aff_transformation_2;
typedef Threetuple<RT> Rep;
typedef typename R_::template Handle<Rep>::type Base;
Base base;
public:
typedef R_ R;
VectorH2() {}
VectorH2(const Point_2& a, const Point_2& b)
{ *this = R().construct_vector_2_object()(a, b); }
VectorH2(const Segment_2& s)
{ *this = R().construct_vector_2_object()(s); }
VectorH2(const Ray_2& r)
{ *this = R().construct_vector_2_object()(r); }
VectorH2(const Line_2& l)
{ *this = R().construct_vector_2_object()(l); }
VectorH2(const Null_vector &)
: base (RT(0), RT(0), RT(1)) {}
VectorH2(const RT& x, const RT& y)
: base (x, y, RT(1)) {}
VectorH2(const RT& x, const RT& y, const RT& w )
{
if ( w >= RT(0) )
base = Rep( x, y, w);
else
base = Rep(-x, -y, -w);
}
bool operator==( const VectorH2<R>& v) const;
bool operator!=( const VectorH2<R>& v) const;
bool operator==( const Null_vector&) const;
bool operator!=( const Null_vector& v) const;
const RT & hx() const { return get(base).e0; };
const RT & hy() const { return get(base).e1; };
const RT & hw() const { return get(base).e2; };
FT x() const { return FT(hx()) / FT(hw()); };
FT y() const { return FT(hy()) / FT(hw()); };
FT cartesian(int i) const;
const RT & homogeneous(int i) const;
FT operator[](int i) const;
int dimension() const;
Direction_2 direction() const;
Vector_2 transform(const Aff_transformation_2& t ) const;
Vector_2 perpendicular(const Orientation& o ) const;
Vector_2 operator+(const VectorH2 &v) const;
Vector_2 operator-(const VectorH2 &v) const;
Vector_2 operator-() const;
Vector_2 opposite() const;
FT squared_length() const;
Vector_2 operator/(const RT &f) const;
Vector_2 operator/(const FT &f) const;
// undocumented:
VectorH2(const Direction_2 & dir)
: base ( dir) {}
VectorH2(const Point_2 & p)
: base ( p) {}
};
template < class R >
inline
bool
VectorH2<R>::operator==( const Null_vector&) const
{ return (hx() == RT(0)) && (hy() == RT(0)); }
template < class R >
inline
bool
VectorH2<R>::operator!=( const Null_vector& v) const
{ return !(*this == v); }
template < class R >
CGAL_KERNEL_INLINE
bool
VectorH2<R>::operator==( const VectorH2<R>& v) const
{
return ( (hx() * v.hw() == v.hx() * hw() )
&&(hy() * v.hw() == v.hy() * hw() ) );
}
template < class R >
inline
bool
VectorH2<R>::operator!=( const VectorH2<R>& v) const
{ return !(*this == v); } /* XXX */
template < class R >
CGAL_KERNEL_INLINE
typename VectorH2<R>::FT
VectorH2<R>::cartesian(int i) const
{
CGAL_kernel_precondition( (i==0 || i==1) );
if (i==0)
return x();
return y();
}
template < class R >
CGAL_KERNEL_INLINE
const typename VectorH2<R>::RT &
VectorH2<R>::homogeneous(int i) const
{
CGAL_kernel_precondition( (i>=0) && (i<=2) );
if (i==0)
return hx();
if (i==1)
return hy();
return hw();
}
template < class R >
inline
typename VectorH2<R>::FT
VectorH2<R>::operator[](int i) const
{ return cartesian(i); }
template < class R >
inline
int
VectorH2<R>::dimension() const
{ return 2; }
template < class R >
CGAL_KERNEL_INLINE
typename VectorH2<R>::Direction_2
VectorH2<R>::direction() const
{ return Direction_2(hx(), hy()); }
template < class R >
inline
typename VectorH2<R>::Vector_2
VectorH2<R>::operator-() const
{ return VectorH2<R>(- hx(), - hy(), hw() ); }
template < class R >
inline
typename VectorH2<R>::Vector_2
VectorH2<R>::opposite() const
{ return VectorH2<R>(- hx(), - hy(), hw() ); }
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::Vector_2
VectorH2<R>::operator+(const VectorH2<R>& v) const
{
return VectorH2<R>( hx()*v.hw() + v.hx()*hw(),
hy()*v.hw() + v.hy()*hw(),
hw()*v.hw() );
}
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::Vector_2
VectorH2<R>::operator-(const VectorH2<R>& v) const
{
return VectorH2<R>( hx()*v.hw() - v.hx()*hw(),
hy()*v.hw() - v.hy()*hw(),
hw()*v.hw() );
}
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::FT
VectorH2<R>::squared_length() const
{
typedef typename R::FT FT;
return
FT( CGAL_NTS square(hx()) + CGAL_NTS square(hy()) ) /
FT( CGAL_NTS square(hw()) );
}
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::Vector_2
VectorH2<R>::operator/(const typename VectorH2<R>::RT& f) const
{ return VectorH2<R>( hx(), hy(), hw()*f ); }
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::Vector_2
VectorH2<R>::operator/(const typename VectorH2<R>::FT& f) const
{ return VectorH2<R>( hx()*f.denominator(), hy()*f.denominator(),
hw()*f.numerator() ); }
template < class R >
CGAL_KERNEL_INLINE
typename R::Vector_2
VectorH2<R>::perpendicular(const Orientation& o) const
{
CGAL_kernel_precondition(o != COLLINEAR);
if (o == COUNTERCLOCKWISE)
return typename R::Vector_2(-hy(), hx(), hw());
else
return typename R::Vector_2(hy(), -hx(), hw());
}
template < class R >
inline
typename R::Vector_2
VectorH2<R>::
transform(const typename VectorH2<R>::Aff_transformation_2& t) const
{ return t.transform(*this); }
#ifndef CGAL_NO_OSTREAM_INSERT_VECTORH2
template < class R >
std::ostream &
operator<<(std::ostream &os, const VectorH2<R> &p)
{
switch(os.iword(IO::mode))
{
case IO::ASCII :
return os << p.hx() << ' ' << p.hy() << ' ' << p.hw();
case IO::BINARY :
write(os, p.hx());
write(os, p.hy());
write(os, p.hw());
return os;
default:
return os << "VectorH2(" << p.hx() << ", "
<< p.hy() << ", "
<< p.hw() << ')';
}
}
#endif // CGAL_NO_OSTREAM_INSERT_VECTORH2
#ifndef CGAL_NO_ISTREAM_EXTRACT_VECTORH2
template < class R >
std::istream &
operator>>(std::istream &is, VectorH2<R> &p)
{
typename R::RT hx, hy, hw;
switch(is.iword(IO::mode))
{
case IO::ASCII :
is >> hx >> hy >> hw;
break;
case IO::BINARY :
read(is, hx);
read(is, hy);
read(is, hw);
break;
default:
std::cerr << "" << std::endl;
std::cerr << "Stream must be in ascii or binary mode" << std::endl;
break;
}
p = VectorH2<R>(hx, hy, hw);
return is;
}
#endif // CGAL_NO_ISTREAM_EXTRACT_VECTORH2
CGAL_END_NAMESPACE
#endif // CGAL_HOMOGENEOUS_VECTOR_2_h
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